Treatment of cellulosic textile material to increase its water absorbency



Patented Nov. 28, 1950 TREATMENT OF CELLULOSIC TEXTILE MATERIAL TO INCREASE ITS WATER ABSORBEN-GY David M. Musser, East Orange, N. 5., assignor to Pacific Mills, Boston, Mass, a corporation of Massachusetts No Drawing. Application August 18, 1948, Serial No. 44,986

(01. s ns) 3 Claims.

The present invention relates to the treatment of cellulosic textile materials for the purpose of enhancing their rate of water absorbency without weakening them.

It is an object of the invention to increase the rate of absorbency of cellulosic textile materials. Another object is to produce a cellulosic fabric in which this desirable property is enhanced without weakening of the fabric.

In accordance with my invention, cellulosic textile material, e. g., fabric, yarns, slivers, threads, etc., is treated under pressure, at a temperature above the boiling point of water, in an alkaline aqueous solution, such as a solution containing an alkali metal hydroxide, at a pH in the range 11 to 13, with a water-soluble alkyl phosphate, or an alkyl alkali metal phosphate, the alkyl group of which contains more than three and less than six carbon atoms. Examples are tributyl phosphate and sodium butyl phosphate.

The treatment is carried only to the point where the rate of absorbency of the fabric is materially enhanced but the physical strength of the cellulose is not impaired. I have found that treatment at pressures from to 25 pounds per square inch for from 2 to 14 hours produces these results when the treating solution contains the alkyl phosphate in an amount greater than 0.1% but not more than 5% of the weight of the fabric being treated.

The following specific examples of my process are given for a better understanding of my invention.

Example 1.--Desized grey terry cloth was kier boiled for eight hours at 15 lbs. steam pressure in an aqueous solution containing by weight 2% sodium hydroxide, 1% sodium carbonate, 0.5% pine oil and tributyl phosphate in amount equal to 5% of the weight of the fabric being treated. The sample was washed, soured, bleached (1 Twad. for one hour at room temperature), washed, soured, and again washed.

Example 2.--The treatment was the same as in Example 1, except that the kier boiling solution contained sodium butyl phosphate instead of the tributyl phosphate of Example 1.

The samples treated in this manner showed a greater rate of wick-up than similar samples treated by a similar method omitting the tributyl phosphate. The rate of absorption of water by the yarn of these samples was tested by the wick-up method as described in Federal Standard Stock Catalogue No. DDD-T-5l1, January 1934, F-3a.

Example 3.-A laboratory autoclave was charged with twelve liters of aqueous solution containing 240 g. sodium hydroxide and 600 g. sodium butyl phosphate (Monsanto 60% solution, pH 7.0) and the following samples were enclosed in separate cloth bags and immersed in the solution:

Viscose fibre, dull, 3 denier, 1 -6" Bale BT Viscose fibre, bright, 1 /2 denier, 11 -6" The autoclave was heated at 15 pounds steam pressure for five hours, the samples were then washed, soured and bleached as in Examples 1 and 2.

The rate of absorption of these samples was tested by the Eichler method (Chem. Abstracts, 34. 8290 (1940)).

The product of my invention has a substantially enhanced rate of absorbency and this desirable property is obtained without significant weakening of the cellulosic textile material.

While the invention is not limited to any particular theory, the following is suggested as an explanation of the markedly improved results obtained by my treatment.

I believe the results observed are attributable to the efficient removal of pectins, waxes, and impurities from the surface of the cellulose through combined emulsification, saponification and solution. The soluble alkali metal phosphates act like soda ash and caustic solutions and under boiling conditions aid in removal of impurities from the fabric mainly through saponification and the formation of soluble salts of such impurities. Alkyl phosphates, and particularly the alkali metal alkyl phosphates, act as emulsifying agents and therefore act to remove impurities from the fabric Whether or not said impurities are saponifiable. In addition, there is present some butyl or amyl alcohol which dissolves some of the waxes. Thus the efficiency of the process is accounted for in large measure by the particular combination of saponifying agents, emulsifying agents and organic solvent present in my treating liquor under the conditions stated.

Butyl phosphate without caustic has little if any effect in increasing the absorbency of cellulosic fabric. Caustic without butyl phosphate has some effect, but as was pointed out above its main action is that of saponification and formation of soluble salts. The combination of the twocaustic plus butyl phosphate-produces the emulsifying agents and butyl alcohol as indicated in the equations.

The term alkyl phosphate as used in the appended claims includes both alkyl phosphates and alkyl alkali metal phosphates.

I claim:

1. A method for enhancing the rate of water absorbency of cellulose textile material without weakening the material, which comprises immersing the cellulose textile material in an alkaline aqueous solution containing sufiicient alkali metal hydroxide to bring the pH of the solution into the range 11 to 13, and an amount between 0.1 and 5% by weight of the textile material of an alkyl phosphate in which the alkyl group contains more than 3 and less than 6 carbon atoms, and maintaining the textile material in said solution under from 5 to 25 pounds pressure and at 4 a temperature above the boiling point of water for from 2 to 14 hours.

2. A method for enhancing the rate of water absorbency of cellulose textile material, without weakening the material, which comprises immersing the cellulose textile material in an alkaline aqueous solution containing sufficient alkali metal hydroxide to bring the pH of the solution into the range 11 to 13, and an amount between 0.1% and 5% by weight of the textile material of sodium butyl phosphate, and maintaining the textile material in said solution under from 5 to 25 pounds pressure and at a temperature above the boiling point of water for from 2 to 14 hours.

3. A method for enhancing the rate of water absorbency of cellulose textile material, without weakening the material, which comprises immersing the cellulose textile material in an alkaline aqueous solution containing suflicient alkali metal hydroxide to bring the pH of the solution into the range 11 to 13, and an amount between 0.1% and 5% by weight of the textile material of tributyl phosphate, and maintaining the textile material in said solution under from 5 to 25 pounds pressure and at a temperature above the boiling point of water for from 2 to 14 hours.

DAVID M. MUSSER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,944,530 Schonburg Jan. 23,, 1934 2,114,669 Schneider Apr. 19,1938 2,253,242 MacMahon et al. Aug. 19, 1941 2,319,822 Moody et al. May 25, 1943v 2,466,393 Dickey et a1 Apr. 5, 1949 

1. A METHOD FOR ENHANCING THE RATE OF WATER ABSORBENCY OF CELLULOSE TEXTILE MATERIAL WITHOUT WEAKENING THE MATERIAL, WHICH COMPRISES IMMERSING THE CELLULOSE TEXTILE MATERIAL IN A ALKALINE AQUEOUS SOLUTION CONTAINING SUFFICIENT ALKALI METAL HYDROXIDE TO BRING THE PH OF THE SOLUTION INTO THE RANGE 11 TO 13, AND AN AMOUNT BETWEEN 0.1% AND 5% BY WEIGHT OF THE TEXTILE MATERIAL OF AN ALKYL PHOSPHATE IN WHICH THE ALKYL GROUP CONTAINS MORE THAN 3 AND LESS THAN 6 CARBON ATOMS, AND MAINTAINING THE TEXTILE MATERIAL IN SAID SOLUTION UNDER FROM 5 TO 15 POUNDS PRESSURE AND AT A TEMPERATURE ABOVE THE BOILING POINT OF WATER FOR FROM 2 TO 14 HOURS. 